JPH0247022Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of an inkjet printer using a drum scanning type on-demand head.

[Conventional technology]

FIG. 4 is a perspective view of the printing section in a conventional inkjet printer, and FIG. 5 is an explanatory diagram showing the positional relationship between the carriage arm and the slider shaft. A pair of slider shafts 22, 2 arranged
3, both ends of the carriage arm 24, which has an arc shape and has a plurality of ink ejecting heads 25a, 25b, 25c, and 25d in the middle part, are connected to the guide cylinder 2, respectively.
4a and rollers 24b so as to be slidable. The drum 21 is connected to a motor (not shown) to rotate at high speed in the direction of the arrow, and the ink ejecting heads 25a, 25b to 25d are connected to the drum 21.
The carriage arm 24 is made to face each other in the circumferential direction to perform so-called main scanning, while the carriage arm 24 is driven by a motor (not shown) connected to a wire 24c connected to one end of the carriage arm 24.
4. If reduced, the ink ejecting heads 25a, 25
b, 25c, and 25d are moved in the axial direction while facing the surface of the drum 21, that is, sub-scanning is performed.

[Problem that the invention attempts to solve]

By the way, in the conventional device as described above, as is clear from FIG. 5, the front slider shaft 2
2 is installed lower than the rear slider shaft 23 by h, and the center of gravity G of the carriage arm 24 is
is significantly higher than either of the slider shafts 22 and 23, so the slider shaft 2
If there is any looseness in the sliding mechanism between 2 and 23 and the carriage arm 24, the center of gravity will change each time the carriage arm 24 stops moving, resulting in lack of smoothness.
The carriage arm 24, in other words, the ink ejecting head, has been shaken, causing printing misalignment.

[Means for solving problems]

The present invention was developed in view of the above circumstances, and its purpose is to reduce the swing of the center of gravity due to movement of the carriage arm by locating the center of gravity of the carriage arm close to the line connecting the slider shafts. To provide an inkjet printer in which the movement of a carriage arm is smooth, the influence of rattling between the carriage arm and a slider shaft can be suppressed as much as possible, and the function of preventing printing misalignment can be greatly improved. be.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof. Fig. 1 is a schematic diagram of an inkjet printer according to the present invention, Fig. 2 is an enlarged perspective view of the carriage arm, and Fig. 3 is an explanatory diagram showing the positional relationship between the carriage arm and the slider shaft. , 2 is a front slider shaft, 3 is a rear slider shaft, 4 is a carriage arm, and 5a, 5b, 5c, and 5d are ink ejecting heads.

Both ends of the drum 1 are pivotally supported by bearings (not shown), and one shaft is connected to a motor _M1 via a pulley provided here and a belt stretched over the drum, and is driven by the motor _M1 . It is designed to be able to be rotated at different speeds. In the front and rear areas of the drum 11, a front slider shaft 2 and a rear slider shaft 3 are arranged parallel to each other and horizontally, and a carriage arm 4 extends across both shafts 2, 2 in the longitudinal direction of both shafts 2, 3. It is slidably mounted on a shelf.

The carriage arm 4 includes a connecting shaft 4c with two plates 4a and 4b interposed between them, and a block 4.
d, 4e, etc. are parallel and integrally connected, and when viewed from the side, as shown in FIGS. 2 and 3, the upper surface side is approximately flat, and the lower surface facing the surface of the drum 1 is the drum. 1. The mounting bases 6a, 6b, 6c, and 6 are respectively formed in an arc shape along one surface.
Ink ejecting heads 5a, 5b, 5c,
5d are removably mounted so as to face the surface of the drum 1, respectively.

A guide tube 4f is provided at one end of the carriage arm 4 on the side facing the rear slider shaft 3.
However, at the other end facing the front slider shaft 2, a pair of upper and lower sliding pieces 4g and 4h are fixed to the blocks 4e and 4d, respectively, and a guide tube 4f is slidably fitted onto the rear slider shaft 3. In addition, the sliding pieces 4g and 4h are brought into sliding contact with the front slider shaft 2 from above and below, so that the drum 1
is mounted so as to be slidable in the axial direction. A looped wire 4i is connected to the block 4e so that it can be reciprocated in the axial direction of the slider shafts 2 and 3, in other words, in the axial direction of the drum 1, by the drive of a motor _M2 . .

Then, the carriage arm 4 is connected to the front slider shaft 2 and the rear slider shaft 3 as described above.
As shown in Fig. 3, when the slider shaft is mounted on the slider shaft, its center of gravity _G0 is located only a distance b higher than the line connecting the centers of both slider shafts 2 and 3, and is very close to each other. ing.

〔effect〕

As described above, in this product, the center of gravity of the carriage arm is located close to the line connecting the center lines of the slider arms on which both ends of the carriage arm are mounted, so there is less vibration due to movement or stopping of the carriage arm, and The influence of rattling that exists in the sliding part with the slider shaft is also reduced,
Smooth movement becomes possible and the ability to prevent blurring in printing is greatly improved. In the present invention, the slider shaft itself does not need to have a special shape, and this configuration can be adopted without major design changes from conventional products, and the present invention has excellent effects.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the proposed product, Figure 2 is an enlarged perspective view of the main parts of the proposed product, Figure 3 is an explanatory diagram showing the positional relationship of the carriage arm and slider shaft, and Figure 4 is an enlarged perspective view of the conventional product. , FIG. 5 is an explanatory diagram of a conventional carriage arm. 1...Drum, 2...Front slider shaft, 3...Rear slider shaft, 4...Carriage arm, 5a, 5b, 5c, 5d...Ink ejection head, 6a, 6b, 6c, 6d...Mounting base.

Claims (1)

[Scope of claim for utility model registration] The drum on which the printing paper is mounted, the front of this drum,
two slider shafts disposed parallel to the drum in the rear region; and a slider shaft movably spanned over the two slider shafts in the axial direction of the drum, with a surface facing the drum paralleling the drum surface. In the inkjet printer, the carriage arm is provided with a carriage arm formed in a substantially arc shape and an ink head disposed on a surface of the carriage arm facing the drum, wherein the center of gravity of the carriage arm is close to a line connecting the two slider shafts. An inkjet printer characterized in that it is configured so that it can be positioned as